Combined device comprising a venous blood reservoir and a cardiotomy reservoir in an extracorporeal circuit

ABSTRACT

A combined device having a reservoir for venous blood and a reservoir for cardiotomy blood is disclosed. The device is characterized in that the venous reservoir is separated from the cardiotomy reservoir by a partition which includes a plurality of apertures. The apertures are in fluid communication with a plurality of ducts and passageways which are configured to provide various modes of operation depending upon whether, for the particular surgical conditions, it is desired to mix venous and cardiotomy blood, or to isolate those blood pools from each other.

[0001] This is a continuation of application Ser. No. 08/888,777, filedJul. 7, 1997, the contents of which are hereby incorporated herein byreference.

FIELD OF THE INVENTION

[0002] The present invention is in the field of devices for use insurgical procedures. More particularly, the present invention relates toa device having both a venous blood reservoir and a cardiotomy reservoirfor use in an extracorporeal circuit.

BACKGROUND OF THE INVENTION

[0003] Many surgical operations involve circulating the blood of apatient through an extracorporeal circuit. In particular, manyopen-heart surgical procedures require that the patient's heart bestopped, and that various biological functions (i.e., blood circulationand oxygenation) be performed mechanically by various devices includedin the extracorporeal circuit. In addition to a pump and to the tubingthrough which the blood will flow, devices including oxygenators, heatexchangers, and blood accumulation reservoirs may be employed. Each ofthese devices is monitored and managed by persons who may be present inthe operating room, or at remote monitoring and control stations.

[0004] One type of blood accumulation reservoir used in such proceduresis a venous reservoir. The venous reservoir serves as a receptacle forblood, typically blood that has been removed from the patient through avein, which is subsequently oxygenated and further processed prior tobeing recirculated back to the patient. Thus, the venous reservoirtypically serves to collect blood as it first enters the extracorporealcircuit. The use of the venous reservoir enables the operator to controlthe blood flow rate, blood pressure, blood volume and related parametersnecessary to maintaining the patient during the surgical procedure.

[0005] A second type of blood accumulation reservoir used in suchprocedures is a cardiotomy reservoir. The cardiotomy reservoir is usedto contain blood which has been collected from the operating field.Blood collected in the cardiotomy reservoir can be reinfused into thepatient after being filtered to remove any clots or other unwantedcontaminants.

[0006] Since the space in the operating room available to operators isoften limited, devices have been proposed which combine the venousreservoir and the cardiotomy reservoir in a single structure. In suchdevices, inlets for the venous blood and for the blood from theoperating field are separated from one another. Blood entering thedevice is filtered and then collected in a common chamber.

[0007] These devices, however, are known to have certain disadvantages.For example, the surface area of such devices which comes into contactwith the blood is relatively large. As a result, the blood becomessusceptible to damage or coagulation. Additionally, even underrelatively normal operating conditions, retrograde blood flow may beinduced, causing the blood to be reverse filtered. This is particularlyproblematic if only venous blood is being collected, because theretrograde flow causes the blood to be sequestered within the cardiotomyfilter, thereby reducing the volume of blood available for oxygenationand recirculation to the patient.

OBJECTS AND SUMMARY OF THE INVENTION

[0008] One object of the present invention is to provide a combineddevice having both a venous blood reservoir and a cardiotomy reservoir.Another object of the invention is to provide a device which allowsvenous blood and cardiotomy blood to be optionally integrated ifsurgical conditions or requirements warrant. Still another object of theinvention is to provide a combined venous blood reservoir and cardiotomyreservoir which minimize blood contact with large surface areas of thedevice and which eliminate the risk of reverse filtration.

[0009] These and other objects of the invention are achieved by acombined device having a venous blood reservoir and a cardiotomyreservoir. The device is characterized in that it includes a housinghaving a partition which separates a lower reservoir from an upperreservoir. The lower reservoir is adapted for use as the venousreservoir, and the upper reservoir is adapted for use as the cardiotomyreservoir. The venous reservoir is provided with a blood inlet connectorand a blood outlet connector, and the cardiotomy reservoir and isprovided with a blood inlet connector and with an air outlet connector.Each of the blood inlet connectors is positioned so that blood enteringthe device is caused to flow through a defoaming substance and a filter.Additionally, the partition which separates the venous reservoir fromthe cardiotomy reservoir is provided with at least two ducts which,starting from apertures formed in the partition, project upward into thecardiotomy reservoir and reach different elevations therein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a sectional view of one embodiment of the invention,taken along a longitudinal plane.

[0011]FIG. 2 is an enlarged sectional view, taken along the plane II-IIof FIG. 1.

[0012]FIG. 3 is the same sectional view of FIG. 2, but with the devicein a different operating mode.

[0013]FIG. 4 is a sectional view, taken along the plane IV-IV of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0014] One embodiment of the device of the present invention is depictedin FIGS. 1-4. Regarding FIGS. 2 and 3, and for the sake of clarity, aview of the device taken along plane II-II of FIG. 1 is shown. In FIGS.2 and 3, the column 16 has been rotated 90° into the page with respectto its position shown in FIG. 1. With reference to the above Figures,the reference numeral 1 designates a housing of the device and thereference numeral 2 designates a partition which divides the spaceenclosed by the housing 1 into a venous reservoir 3, and a cardiotomyreservoir 4. The housing is preferably formed of a transparent polymerto allow the interior of the device to be viewed by an operator.Numerous transparent, medically useful polymers are known to thosehaving ordinary skill in the art.

[0015] The venous reservoir 3 is provided with an venous inlet connector5, terminating at 5 a, for the venous blood. Venous blood entering thevenous reservoir 3 through the venous inlet connector 5 enters adistribution chamber 22 where it is passed outward, in a substantiallyuniform manner, into a central region of the venous reservoir through aplurality of slotted apertures 23 formed in the distribution chamber 22.The central region of the venous reservoir is defined by a generallycylindrical wall 6 of a defoaming material. The defoaming material issurrounded by a filter 6 a through which the blood must also pass as itenters the venous reservoir 3. Blood exits the venous reservoir 3through a venous outlet connector 7.

[0016] In one embodiment, the defoaming material comprises a porouspolymeric material such as a polyurethane foam. In one preferredembodiment, the defoaming material is a polyurethane foam having a poresize of approximately 5 to 50 pores per inch, more preferablyapproximately 20 to 30 pores per inch. The defoaming material mayoptionally be treated with a medically acceptable antifoaming agent suchas a silicone antifoaming agent. The filter is a screen, preferablyformed of a polyester, having an aperture size in the range of about 20to 50 microns.

[0017] The top of the venous reservoir 3 is defined by a partition 2which separates the venous reservoir 3 from the cardiotomy reservoir 4.The cardiotomy reservoir 4 is provided with a cardiotomy inlet connector8 for receiving blood arriving from the operating field, and an airoutlet connector 10. Blood entering the cardiotomy reservoir 4 throughthe cardiotomy inlet 8 first encounters a flow distributor 24, whichdistributes the blood outwardly in a substantially uniform manner. Aswith the blood entering the venous reservoir, the blood next encountersa generally cylindrical wall 9 of a defoaming material. The defoamingmaterial is surrounded by a filter 9 a through which the blood must alsopass as it enters the cardiotomy reservoir 4. The defoaming material isas described above, namely, a porous polymeric material such as apolyurethane foam. As before, in one preferred embodiment, the defoamingmaterial is a polyurethane foam having a pore size of approximately 5 to50 pores per inch, more preferably approximately 20 to 30 pores perinch, and the filter is a screen, preferably formed of a polyester,having an aperture size in the range of about 20 to 50 microns.

[0018] The partition 2 which separates the venous and cardiotomyreservoirs is typically a substantially flat plate. When the device isin operation, it is positioned in a manner that maintains the partitionin a substantially horizontal orientation. The partition 2 is providedwith a plurality of apertures that provide for operation of the devicein the manner discussed below.

[0019] In one embodiment, shown in FIGS. 1-3, the partition 2 includestwo apertures 11 and 12, from which extend two ducts 13 and 14. Theducts preferably extend substantially at right angles to partition 2 andtherefore are maintained in a vertical orientation when the device isoriented in its proper operating position. The ducts 13 and 14 extendinto the cardiotomy reservoir 4 and reach approximately the sameelevation. The upper edge of each duct is typically provided with aplurality of axial notches 15.

[0020] An axially moveable column 16 is positioned preferably in thecenter of the cardiotomy reservoir 4 and extends upward through thehousing 1. The column 16 includes a first passageway 17 and a secondpassageway 18. In the first passageway 17, a lower end 17 a communicateswith the venous reservoir 3 through a central aperture 20 in thepartition 2, and an upper end 17 b communicates with the cardiotomyreservoir 4. Likewise, in the second passageway 18, a lower end 18 acommunicates with the cardiotomy reservoir 4 and an upper end 18 bcommunicates with the exterior of the housing.

[0021] Column 16 can be caused to move axially by manual action on tab19. As such, the column can be moved between a lower stroke limitposition, illustrated in FIGS. 1 and 2, and an upper stroke limitposition, shown in FIG. 3. While in the lower stroke position, the lowerend 17 a of the first passageway is sealingly inserted into a centralaperture 20 provided preferably at the center of the partition 2. Theseal may optionally be enhanced through the use of an O-ring 25positioned around the exterior of the lower end 17 a of the firstpassageway. The seal, when engaged, serves to prevent blood in thecardiotomy reservoir from entering the venous reservoir. When the sealis engaged, the upper end 17 b of the first passageway is caused to bepositioned at an elevation which is above that of the upper edges of theducts 13 and 14. Alternatively, when the column 16 is moved into itsupper stroke position, the lower end 17 a of the first passageway 17 isextracted from the central aperture 20, thereby disengaging the seal andallowing blood in the cardiotomy reservoir 4 to flow directly into thevenous reservoir 3. It should be noted that regardless of the positionof the column 16, fluid communication through the second passageway 18is substantially unaffected. A second O-ring 27 may optionally beprovided around the exterior of an upper portion of the column 16. Thesecond O-ring 27 serves to provide a seal between the upper portion ofthe column and the portion of the housing 1 through which the columnpasses.

[0022] When the column 16 is at the lower stroke limit, i.e., in theposition shown in FIGS. 1 and 2, blood flowing into venous inletconnector 5 enters the venous reservoir 3. If the amount of bloodentering the venous reservoir is greater than the amount exiting throughthe venous outlet connector 7, the level of blood inside the venousreservoir 3 is caused to rise. It is possible that the rising level ofblood can lead to the complete filling of the venous reservoir. At thispoint, one advantage of the present invention becomes apparent, since anadditional accumulation of blood is allowed because the blood can enterthe ducts 13 and 14, as well as the first passageway 17. Such excessblood can then rise in the ducts and passageway until it overflows intothe cardiotomy reservoir 4 through the ducts 13 and 14. By integratingthe venous reservoir 3 and the cardiotomy reservoir 4, the device,whenever necessary, allows the accumulation of an amount of venous bloodwhich is far greater than the capacity of the venous reservoir alone.

[0023] Integration of the venous and cardiotomy reservoirs also allowsair and other gaseous emboli entrained in the venous blood, resultingfor example from poor cannulation, to be released from the device bypassing through the ducts 13, 14 and the first passageway 17 andallowing it to collect in the upper portion of the cardiotomy reservoir4, from which it may exit or be withdrawn through the air outletconnector 10.

[0024] Likewise, the functionality of the cardiotomy reservoir 4 is alsoenhanced. Specifically, blood entering the cardiotomy reservoir 4through the cardiotomy inlet connector 8 gradually rises in thatreservoir until it is almost filled. Rather than completely filling thecardiotomy reservoir, however, once the blood reaches a certain level,it is caused to enter the ducts 13 and 14 and flow downwardtherethrough, accumulating in the venous reservoir 3. As such, thedevice is configured to allow excess accumulation of either venous orcardiotomy blood.

[0025] Even if excess cardiotomy blood is flowing into the venousreservoir, air and other gaseous emboli present in the venous blood canstill be removed from the device. Since the upper end 17 b of thepassageway 17 is configured to remain above the upper edges of the ducts13 and 14, even if the ducts are communicating blood into the venousreservoir, the passageway 17 remains blood-free and capable ofcommunicating air from the venous reservoir into the cardiotomyreservoir, and ultimately, to the exterior of the housing through theair outlet connector 10.

[0026] When the column 16 is positioned at its upper stroke limit, asshown in FIG. 3, all of the blood contained in the cardiotomy reservoir4 will flow into the underlying venous reservoir 3 through the centralaperture 20. As such, in this configuration, the central aperture 20acts as a drainage port which may be plugged and unplugged by the column16.

[0027] Finally, it should be noted that a situation can arise in whichthe operator does not wish to mix blood contained in the cardiotomyreservoir 4 with blood contained in the venous reservoir 3. This canoccur, for example, if undesirable substances are present in thecardiotomy blood. In that situation, the blood contained in thecardiotomy reservoir is effectively isolated from the blood in thevenous reservoir and can be completely removed from the device throughpassageway 18.

[0028] It should be noted that the advantages of the device of thepresent invention are not intended to be strictly limited to thosedescribed above. For example, in the embodiments of the device shown inFIGS. 1-4, the amount of blood contact with the internal surfaces of thedevice has been minimized, as has the possibility of reverse filtrationof blood contained within the device. Furthermore, due to the relativelynon-complex design and operation of the device, the device will respondrapidly to control manipulations by the operator.

[0029] Of course, the described invention is amenable to numerousmodifications and variations, all of which are intended to be within thescope of the inventive concept. Thus, for example, the number of ductsprovided on the partition can be different from the configurationdescribed.

[0030] Likewise, the invention is not intended to be limited to theparticular materials employed, nor to the shapes or any dimensionsemployed. Rather, the device may be made according to the specificrequirements of a particular application for which its use is intended.

[0031] Equivalents

[0032] Various modifications and alterations to this invention willbecome apparent to those skilled in the art without departing from thescope and spirit of this invention. It should be understood that thisinvention is not intended to be unduly limited by the illustrativeembodiments and examples set forth herein and that such examples andembodiments are presented by way of example only with the scope of theinvention intended to be limited only by the claims set forth herein asfollows.

What is claimed is:
 1. A combined blood reservoir which comprises: a) afirst reservoir for receiving and containing venous blood; b) a secondreservoir for receiving and containing cardiotomy blood; c) the firstand second reservoirs being in fluid communication such that eitherreservoir can overflow into the other; and d) a passageway which allowsa gas to communicate between the reservoirs, wherein such communicationcan occur even when one reservoir is overflowing into the other.
 2. Thecombined blood reservoir of claim 1 wherein the first reservoir will notoverflow into the second reservoir until the first reservoir contains afirst, predetermined volume of fluid.
 3. The combined blood reservoir ofclaim 1 wherein the second reservoir will not overflow into the firstreservoir until the second reservoir contains a second, predeterminedvolume of fluid.
 4. The combined blood reservoir of claim 1 wherein thefirst reservoir is separated from the second reservoir by a partition.5. The combined blood reservoir of claim 4 wherein the passageway ismoveable between a lower position and an upper position, the passagewaybeing such that when it is moved into the lower position, its lower endsealingly mates with an aperture in the partition to provide fluidcommunication between the first and second reservoirs though thepassageway, and when it is moved into the upper position, it allowsfluid communication between the first and second reservoirs through theaperture.
 6. A method for storing venous and cardiotomy blood during asurgical procedure which comprises: a) providing a combined bloodreservoir which comprises: i) a first reservoir for receiving andcontaining venous blood; ii) a second reservoir for receiving andcontaining cardiotomy blood; iii) the first and second reservoirs beingin fluid communication such that either reservoir can overflow into theother; and iv) a passageway which allows a gas to communicate betweenthe reservoirs, wherein such communication can occur even when onereservoir is overflowing into the other; b) connecting the firstreservoir to a source of venous blood; c) connecting the secondreservoir to a source of cardiotomy blood; and d) collecting venous andcardiotomy blood in the first and second reservoirs, respectively. 7.The method of claim 6 wherein the first reservoir is separated from thesecond reservoir by a partition.
 8. The method of claim 7 which includesthe further step of mounting the combined blood reservoir in a mannersuch that the partition is maintained in a substantially horizontalorientation.
 9. A combined blood reservoir which comprises: a) a venousreservoir for containing venous blood, the venous reservoir having avenous blood inlet and a venous blood outlet; b) a cardiotomy reservoirfor containing cardiotomy blood, the cardiotomy reservoir positionedabove the venous reservoir and having a cardiotomy blood inlet and a gasoutlet; c) a partition which separates the venous reservoir from thecardiotomy reservoir, the partition including a plurality of aperturescapable of providing fluid communication between the venous reservoirand the cardiotomy reservoir; d) at least one duct extending upward fromat least one aperture, the duct having an upper outlet contained withinthe cardiotomy reservoir; and, e) at least one passageway having a lowerend and an upper end, the lower end of the passageway mating with oneaperture in the partition to provide fluid communication between thepassageway and the venous reservoir, and further having an upper endwhich extends into the cardiotomy reservoir to an elevation that isabove that of the upper outlet of the at least one duct.
 10. Thecombined blood reservoir of claim 9, wherein the passageway is moveablebetween a lower position and an upper position, the passageway beingsuch that when it is moved into the lower position, its lower endsealingly mates with one aperture in the partition to provide fluidcommunication between the passageway and the venous reservoir, and whenit is moved into the upper position, it allows fluid communicationbetween the cardiotomy reservoir and the venous reservoir through theaperture.
 11. The combined blood reservoir of claim 9, wherein bloodentering the venous reservoir through the venous blood inlet is causedto pass through a defoaming substance and a filter.
 12. The combinedblood reservoir of claim 9, wherein blood entering the cardiotomyreservoir through the cardiotomy blood inlet is caused to pass through adefoaming substance and a filter.
 13. The combined blood reservoir ofclaim 9, wherein blood entering the venous reservoir from the cardiotomyreservoir is caused to pass through a defoaming substance and a filter.14. The combined blood reservoir of claim 10, wherein the movablepassageway is contained within a column that can be manually actuated byan operator.
 15. The combined blood reservoir of claim 14, wherein thecolumn includes a second passageway which provides fluid communicationbetween the cardiotomy reservoir and the exterior of the device.
 16. Thecombined blood reservoir of claim 9, wherein the partition comprises asubstantially flat plate.
 17. The combined blood reservoir of claim 16,wherein the partition is maintained in a substantially horizontalorientation during operation of the device.
 18. A combined bloodreservoir which comprises: a) a venous reservoir for containing venousblood, the venous reservoir having a venous blood inlet and a venousblood outlet; b) a cardiotomy reservoir for containing cardiotomy blood,the cardiotomy reservoir positioned above the venous reservoir andhaving a cardiotomy blood inlet and a gas outlet; c) a partition whichseparates the venous reservoir from the cardiotomy reservoir, thepartition including a plurality of apertures capable of providing fluidcommunication between the venous reservoir and the cardiotomy reservoir;d) at least one duct extending upward from at least one aperture, theduct having an upper outlet contained within the cardiotomy reservoir;and, e) at least one passageway having a lower end and an upper end andbeing moveable relative to the partition, the passageway being such thatwhen it is moved into a lower position, its lower end sealingly mateswith one aperture in the partition to provide fluid communicationbetween the passageway and the venous reservoir, and when it is movedinto an upper position, it allows fluid communication between thecardiotomy reservoir and the venous reservoir through the aperture, thepassageway further having an upper end which extends into the cardiotomyreservoir to an elevation that is above that of the upper outlet of theat least one duct.
 19. The combined blood reservoir of claim 18, whereinblood entering the venous reservoir through the venous blood inlet iscaused to pass through a defoaming substance and a filter.
 20. Thecombined blood reservoir of claim 18, wherein blood entering thecardiotomy reservoir through the cardiotomy blood inlet is caused topass through a defoaming substance and a filter.
 21. The combined bloodreservoir of claim 18, wherein blood entering the venous reservoir fromthe cardiotomy reservoir is caused to pass through a defoaming substanceand a filter.
 22. The combined blood reservoir of claim 18, wherein themovable passageway is contained within a column that can be manuallyactuated by an operator.
 23. The combined blood reservoir of claim 18,wherein the column includes a second passageway which provides fluidcommunication between the cardiotomy reservoir and the exterior of thedevice.
 24. The combined blood reservoir of claim 18, wherein thepartition comprises a substantially flat plate.
 25. The combined bloodreservoir of claim 24, wherein the partition is maintained in asubstantially horizontal orientation during operation of the device.